From 8776c15c85322612b9bf79daf50f74be71c12e05 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 9 Mar 2016 10:56:36 -0500
Subject: [PATCH] Fix incorrect tlist generation in create_gather_plan().
This function is written as though Gather doesn't project; but it does.
Even if it did not project, though, we must use build_path_tlist to ensure
that the output columns receive correct sortgroupref labeling.
Per report from Amit Kapila.
---
src/backend/optimizer/plan/createplan.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 0c2d593499..5c06547931 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -1360,11 +1360,17 @@ create_gather_plan(PlannerInfo *root, GatherPath *best_path)
{
Gather *gather_plan;
Plan *subplan;
+ List *tlist;
- /* Must insist that all children return the same tlist */
+ /*
+ * Although the Gather node can project, we prefer to push down such work
+ * to its child node, so demand an exact tlist from the child.
+ */
subplan = create_plan_recurse(root, best_path->subpath, CP_EXACT_TLIST);
- gather_plan = make_gather(subplan->targetlist,
+ tlist = build_path_tlist(root, &best_path->path);
+
+ gather_plan = make_gather(tlist,
NIL,
best_path->path.parallel_degree,
best_path->single_copy,
--
2.49.0